Leishmania-induced inactivation of the macrophage transcription factor AP-1 is mediated by the parasite metalloprotease GP63

• Published in: PLoS pathogens 2010-10, Vol.6 (10), p.e1001148-e1001148
• Main Authors: Contreras, Irazú, Gómez, María Adelaida, Nguyen, Oliver, Shio, Marina T, McMaster, Robert W, Olivier, Martin
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Cells, Cultured; Development and progression; Down-Regulation; Gene Expression Regulation; Genetic aspects; Health aspects; Immune Evasion - genetics; Immune Evasion - physiology; Immunology/Immune Response; Immunology/Immunity to Infections; Immunology/Innate Immunity; Infectious Diseases/Protozoal Infections; Kinases; Leishmania; Leishmania - genetics; Leishmania - physiology; Leishmaniasis; Macrophages; Macrophages - immunology; Macrophages - metabolism; Medical research; Metalloendopeptidases - genetics; Metalloendopeptidases - metabolism; Metalloendopeptidases - physiology; Metalloproteases - metabolism; Metalloproteases - physiology; Mice; Microbiology/Parasitology; Molecular Sequence Data; Organisms, Genetically Modified; Parasites; Parasitic diseases; Physiological aspects; Proteases; Protein Binding - physiology; Protein Processing, Post-Translational - physiology; Proteins; Transcription Factor AP-1 - antagonists & inhibitors; Transcription Factor AP-1 - metabolism
• ISSN: 1553-7374; 1553-7366; 1553-7374
• DOI: 10.1371/journal.ppat.1001148

Leishmania parasites have evolved sophisticated mechanisms to subvert macrophage immune responses by altering the host cell signal transduction machinery, including inhibition of JAK/STAT signalling and other transcription factors such as AP-1, CREB and NF-κB. AP-1 regulates pro-inflammatory cytokines, chemokines and nitric oxide production. Herein we show that upon Leishmania infection, AP-1 activity within host cells is abolished and correlates with lower expression of 5 of the 7 AP-1 subunits. Of interest, c-Jun, the central component of AP-1, is cleaved by Leishmania. Furthermore, the cleavage of c-Jun is dependent on the expression and activity of the major Leishmania surface protease GP63. Immunoprecipitation of c-Jun from nuclear extracts showed that GP63 interacts, and cleaves c-Jun at the perinuclear area shortly after infection. Phagocytosis inhibition by cytochalasin D did not block c-Jun down-regulation, suggesting that internalization of the parasite might not be necessary to deliver GP63 molecules inside the host cell. This observation was corroborated by the maintenance of c-Jun cleavage upon incubation with L. mexicana culture supernatant, suggesting that secreted, soluble GP63 could use a phagocytosis-independent mechanism to enter the host cell. In support of this, disruption of macrophage lipid raft microdomains by Methyl β-Cyclodextrin (MβCD) partially inhibits the degradation of full length c-Jun. Together our results indicate a novel role of the surface protease GP63 in the Leishmania-mediated subversion of host AP-1 activity.